Telescoped caisson



2 Sheets-Sheet 1 Original Filed Sept. 2, 1966 INVENTOR WILLIAM F.MANNING BY ATTORNEY Dec. 9, 1969 w. F. MANNING TELESCOPED CAISSON 2Sheets-Sheet 2 Original Filed Sept. 2, 1966 INVENTOR WILLIAM F. MANNINGUnited States Patent 3,482,408 TELESCOPED CAISSON William F. Manning,Dallas, Tex., assignor to Mobil Oil Corporation, a corporation of NewYork Original application Sept. 2, 1966, Ser. No. 577,040, now PatentNo. 3,426,859, dated Feb. 11, 1969. Divided and this application Mar.29, 1968, Ser. No. 737,259

Int. Cl. E02d /52; E02b 17/00; E21b 7/12 US. CI. 6146 3 Claims ABSTRACTOF THE DISCLOSURE This specification discloses apparatus for drillingand completing an offshore well above the surface of a body ofrelatively shallow water. A two-piece well protector is utilized, thewell protector comprising lower pile and upper caisson sections. Thelower pile section is first driven into the formation underlying themarine bottom with one of the recently developed underwater piledrivers. The caisson section is then lowered into the water and stabbedinto or over the pile section and grout is injected therebetween to formthe composite well protector.

This is a division of application Ser. No. 577,040, filed Sept. 2, 1966,now United States Patent No. 3,426,859.

The present invention is directed to a method and apparatus for drillingand completing an offshore well above the surface of the body of water,in relatively shallow water. More particularly, the invention relates toa twopiece caisson type of well protector which is relatively easy tohandle and requires a minimum of energy to be driven into the subaqueousformations beneath the marine bottom.

Present developments in the offshore oil and gas industry indicate thatdrilling and production efforts will be extended to underwater areassuch as the outer fringes of the continental shelves and the continentalslopes where a submarine production system is the most practical methodof reaching the subaqueous deposits. However, the shallower waters arestill providing an abundance of hydrocarbon deposits. As the moreprolific fields are developed in these shallow waters from above-surfaceplatforms, the industry is searching for less expensive ways of reachingthe subaqueous formations so that the less prolific fields will beeconomically available. One relatively inexpensive device that has beenused extensively, particularly in the Gulf of Mexico, is the caissontype of well protector, either self-supporting or utilized inconjunction with a template or guy lines. At the present time one-piece,or welded up, well protectors are used. Driving the entire length of awell protector is inefficient due to the large mass involved,particularly as the water depth increases. In two hundred feet of water,where it is required that the well protector be driven one hundredtwenty feet or more into the subaqueous formations, the length of thewell protector may even be too long to be brought conveniently into anupright position under the pile driver.

Therefore, it is an aspect of the present invention to provide atwo-piece well protector, each of the sections thereof being shortenough to be easily handled in the upright position by conventionaloffshore derrick barges.

A further aspect of the present invention is to provide a two-piece wellprotector utilizing the advantages of underwater pile driving.

Other aspects and advantages of the present invention will be readilyapparent from the following description, when taken in conjunction withthe accompanying draw ings that illustrate useful embodiments inaccordance with this invention, in which:

FIGURE 1 is a pictorial illustration of a two-piece well "ice protectorof the present invention erected at a marine site for extending asubaqueous well to a point above the surface of a body of water;

FIGURES 2 through 5 illustrate the erecting of the two-piece wellprotector at the marine site in conjunction with an underwaterpiledriver;

FIGURE 6 is a sectional view of a portion of a first embodiment of thewell protector of the present invention illustrating the telescoping ofthe upper section over the lower section which has been driven into thesubaqueous formations underlying the marine bottom; and

FIGURE 7 is an elevational sectional view of a portion of a secondembodiment of the well protector of the present invention illustratingthe stabbing of the uppersection into the lower section which has beendriven into the subaqueous formations underlying the marine bottom.

The present invention relates to a two-piece telescoping well protectorin which the lower, or pile, section is separately driven into thesubaqueous formations by' an underwater pile driving technique. Theinvention further relates to the method of installing the two-piece wellprotector, in which the pile driving o eration is terminated when thepile section extends only the minimum distance above the marine bottomnecessary for later connecting thereto the upper, or caisson, sectiondesigned to project above the surface of the water after installation,and the later step of lowering the caisson section down from the surfaceinto telescopic cooperation with the pile section to form the wellprotector.

Now looking to FIGURE 1 a two-piece well protector, generally designated10, consists of a lower tubular section, hereinafter referred to as apile section 12, anchoring the structure in a marine bottom 13 and anupper tubular section, hereinafter referred to as a caisson section 14,for extending the well protector from the upper terminus of the pilesection 12 to a point above the surface 15 where a small production deck16 is supported a distance above the water necessary to insure thatwaves will not impinge on it, and has extending up therefrom aproduction wellhead 18, completing a subaqueous well, the casings andtubing thereof being hung through the unimpeded throughbore of the wellprotector 10. While the production deck 16 may in some cases be largeenough to accommodate a helicopter, in the more usual instance onlyenough additional space (for example, a common size is 11 x 18) isprovided for a fog signal 20 and personnel working on the wellhead 18. Aflowline 21, supported along the well protector 10 from the upper endthereof to the marine bottom 13, connects the wellhead 18 with a nearbyproduction facility through a portion of the flowline laid on the marinebottom. A circular landing deck 22 is concentrically fixed to thecaisson section 14 at the mean low water line and a ladder 24 extendsbetween the landing deck 22 and the production deck 16 above. While inthis illustration the caisson section 14 is shown as being tapered, andsupported in part, against lateral loads by a plurality of guy lines 26,the remainder of this discussion applies equally as well to a constantdiameter caisson, and to a caisson supported by a template structure, orcompletely self-supporting.

Referring now to FIGURES 2 through 5, the procedure to be followed inerecting a well protector 10 is illustrated. Looking to FIGURE 2, pilesection 12 is held suspended beneath the surface 15 of the body of waterwith its lower end either just above or resting on the marine bottom 13.The pile section 12 is connected at its upper end to a submerged piledriving device, generally designated 28, which is in turn supported froma derrick mounted on a floating barge or mobile platform nearby (notshown), by a releasable connection 30. The connection 30 can be ahydraulically actuated clamp or a simple J-slot connector,

or any other type of connection which can be later remotely released.The pile driving device 28 comprises a casing 32, containing an anviland a hammer (not shown), and a framework 34 extending from the upperend of the casing 32 to the derrick. Communication lines extending fromthe casing 32 to the derrick for actuating the pile driving hammer aresupported within the framework 34.

The pile driving device 28 may be one of those recently developed andoffered to the industry for underwater pile driving and which consistsof a watertight chamber enclosing a pile driving hammer and anvil. Bydriving the hammer up in the chamber with compressed air, and thenreleasing the compressed air so that the hammer will drop down on theanvil, a useful amount of energy can be imparted through the anvil todrive the pile section of the well protector vertically into theformations underlying a marine bottom. A pile driving device of thistype is offered by the MKT Corporation and is described in theirbrochure entitled MKTPile Driving Equipment, published June 1964.

FIGURE 3 shows the pile section 12 after it has been driven the requireddistance into the formations underlying the marine bottom 13. The piledriving device 28 is being withdrawn subsequent to the release of theconnector 30. Enough of the pile section 12 is left extending above themarine bottom 13 for stabbing the caisson section 14 thereover.

In FIGURE 4 the caisson section 14 is suspended from the derrick bargeand is being lowered through the water to be stabbed over the pilesection 12. A landing base and guidelines as described in the RF. Baueret al. Patent No. 2,808,229, issued Oct. 1, 1957, may be utilized toguide the caisson section 14 over the pile section 12. Alternatively jetguiding means hung in the caisson section 14 may be used in conjunctionwith an underwater. televiewer or a driver radioing instructions to thesurface.

FIGURE 5 shows the caisson section 14 stabbed over and grouted to thepile section 12. A conductor pipe 36 is suspended from above the upperend of the well protector and extends therethrough into the marinebottom. 13. The conductor pipe 36 may be jetted, drilled, orhammer-driven into the underlying formations. The drilling rig forhandling the conductor pipe 36, drilling a well therethrough, settingcasings, and the other various operations necessary for completing thewell, as well as the mud tank and other equipment, will be located onfloating barges or jack-up rigs adjacent the well protector 10.

FIGURE 6 shows a first configuration of the well protector 10Acomprising a pile section 12A adapted to have a caisson section 14Astabbed .thereover, A small diameter upper portion 38, and a taperedintermediate portion 40 of the pile section 12A act in conjunction witha stabbing bell 42 on the lower end of the caisson section 14A to permitthe caisson section 14A to be stabbed easily over the pile section 12A.Centering guides 44 are welded within the caisson section 14A to guidethe conductor pipe 36 into the small diameter upper portion 38 of thepile section 12A and to act as stops to prevent the caisson section 14Afrom telescoping too far over the pile section 12A and sinking intounconsolidated surface formations of the marine bottom 13. A releasablegrout line 46 extends the length of the caisson section 14A. At thelower end of the caisson section 14A the grout line 46 is connected to aport through the wall thereof, so that grout can be injected into theannulus or chamber 48 between the caisson section 14A and the pilesection 12A. A grout seal 50 is mounted in the lower end of the caissonsection 14A to prevent the leakage of grout. To hold the caisson section14A rigidly to the pile section 12A while the grout is setting, a remoteballistic connecting device such as that described in my copendingapplication entitled Ballistic Jacket-Pile Connection, Ser. No. 489,527,filed Sept. 23, 1965, may be used.

FIGURE 7 shows a second configuration of the two- .4 piece wellprotector 10B in which the caisson section 14B is designed to be stabbedinto the pile section 12B. In this arrangement a simple tubular pile maybe utilized, the caisson section 14B having a lower tapered portion 52to facilitate the stabbing operation. Spaced a distance up the caissonsection 14B, a plurality of radially positioned guide plates 54 arewelded to the outer surface of the caisson section 14B, the lowertriangular portions of the guide plates 54 acting to center the caissonsection 14B in the pile section 12B while the integral horizontalsurfaces 56 thereabove act to limit the distance which the caissonsection 14B can be stabbed into the pile section 12B. As in the priorembodiment a grout seal is necessary. The grout seal 58 is mounted onthe outside of the caisson section 14B just above the lower taperedsection 52. A grout line 60 would be previously fixed within the caissonsection 14B and connected to a port extending through the caisson wallat the lower end thereof just above the grout seal 58 so that groutcould be injected into the annulus or chamber 62 between the walls ofthe caisson section 14B and the pile section 128. If ballisticconnectors are utilized for this embodiment, they should be fastened tothe outer face of the wall of the pile section 12B prior to its beingdriven into the marine bottom 13.

Although the present invention has been described in connection withdetails of the specific embodiments there of, it is to be understoodthat such details are not intended to limit the scope of the invention.The terms and expressions employed are used in a descriptive and not alimiting sense and there is no intention of excluding such equivalents,in the invention described, as fall within the scope of the claims. Nowhaving described the apparatus and method herein disclosed, referenceshould be had to the claims which follow.

What is claimed is:

1. A marine well protector for supporting a production wellhead or thelike above the surface of a body of water comprising:

a tubular pile section adapted to be positioned partially into thebottom of said body of water, said pile section being of a lengthsufiicient to extend above the bottom after it is in position;

a tubular caisson section adapted to be telescopically fitted to theportion of said pile section which extends above the bottom of said bodyof water when said pile section is in position, said caisson sectionbeing of a length sufificient to extend from adjacent said bottom to apoint above the surface of said body of water; and

means operably associated with said caisson section for connectingpermanently said caisson section to said pile section when said sectionsare in telescoping relationship, said connecting means comprising a lineconnected to said caission section for injection of grout between saidcaisson and pile sections when said sections are in position.

2. A well protector as recited in claim 1 wherein the internaldimensions of said caisson section are larger than the externaldimensions of said pile section whereby said caisson section willtelescope over said pile section and wherein said connecting meansfurther includes:

a stabbing bell fixed to the lower end of said caisson section;

guide means within the lower portion of said caisson section adapted tocenter a conductor pipe lowered through said caisson section and tocoact with the upper portion of said pile section to limit thetelescoping of said caisson section over said pile section;

a grouting chamber formed between the telescoped portions of saidcaisson and pile sections, said line connected to said caisson sectionfor injecting grout in fluid communication with said chamber; and

means fixed to said caisson section for sealing the lower end of saidchamber.

3. A marine Well protector for supporting a production Wellhead or thelike above the surface of a body of Water comprising:

a tubular pile section to be driven into the formations underlying themarine bottom, said pile section being of a length sufficient to supportat least a partial section of said well protector;

a tubular caisson section telescopically fitted to the upper end of saidpile section at the marine bottom, the caisson section being of a lengthsufiicient to extend from the marine bottom to a point above the surfaceof the body of Water; and

means for connecting said pile and said caisson sections togetherwhereby an unimpeded throughbore is formed, said connecting meanscomprising:

a tubular portion of said caisson section for coacting with the openupper portion of said pile section to permit said caisson section to bestabbed into said pile section;

guide means fixed to the outer surface of said caisson section andcoacting with said pile section to center said caisson section withinsaid pile section and to limit the telescoping of said caisson sectionwithin said pile section;

a grouting chamber formed between the portions of said caisson and saidpile sections which are in telescoped relationship;

means fixed to outer section of said caisson section for sealing thelower end of said chamber; and

means for injecting grout into said chamber from above the surface of abody of water, said grout injecting means comprising a grout lineextending through said caisson section and operably connected to saidchamber through the Wall of said caisson section at the lower endthereof.

References Cited UNITED STATES PATENTS 2,906,500 9/1959 Knapp et al61--46.5 X 3,020,956 2/1962 Suderow 61--46.5 3,209,544 10/1965 Borrmann61--46.5

JACOB SHAPIRO, Primary Exagrniner US. Cl. X.R.

